Exposuremeter



Aug. 24, 1943. J, BOLSEY 2,327,858

EXPOSUREMETER Filed Dec. 31, 1940 Patented Aug. 24, 1943 EXPOSUREMETER Jacques Bolsey, New York, N. Y.

Application December 31, 1940, Serial No. 372,505

In Switzerland November 8, 1940 8 Claims.

My present invention relates to reflex cameras, and more particularly to reflex cameras provided with photo-electric means for regulating the exposure setting of the camera.

More specifically, my invention relates to reflex cameras in which a cell-controlled meter for determining the exposure is attached to the camera.

It is an object of my invention to provide an arrangement which enables measurement of the light intensity of the image in the view finder of such a reflex camera as well as measurement of the intensity of the light rays reaching the camera from the object to be photographed.

It is another object of my invention to provide for these two measurements one single exposure meter, adapted to carry out these measurements intermittently, i. e. one after the other.

It is still another object of my invention to secure this exposure meter to the camera in such a manner as to enable easy and quick shifting of the exposure meter from one measuring position into the other, and convenient reading of the pointer indications on the exposure meter scale in either position.

A further object of my invention consists in shaping and arranging the exposure meter and the camera casing themselves, and their parts, in such a manner as to enable direct adjusting of the factors affecting the exposure in accord ance with th indications of the exposure meter.

It is still a further object of my invention to provide a new scale system for the exposure meter arrangements proposed by me.

In order to attain the above objects I propose to provide in a reflex camera a camera casing, a frontal lens in the front wall of said casing, a viewing member in the top wall of said casing, a reflecting mirror within said casing adapted to reflect the light rays entering the casing through said lens onto said viewing member and thus to project an image of the object to be photographed on this member, a photoelectric exposure meter comprising a photoelectric cell and a pointer, and means securing at least said photo-electric cell movably to said camera casing in such a manner as to enable movement of said cell between a position in which its light-sensitive surface faces said viewing member and the image projected on it, and a position in which this surface is directed against the object to be photographed.

In reflex cameras with one single lens only, I use this lens also for focusing purposes by projecting the image of the object to be photographed on the ground glass serving as viewing member; the light intensity of this image is then measured by the exposure meter arrangement described above.

In a preferred embodiment of my invention I use a substantially flat exposure meter comprlsing an exposure meter body, a photoelectric cell arranged on its bottom wall, and a cooperating pointer arranged on its top wall; this exposure meter is secured by hinge-like means along one of its edges to the top wall of the camera casing adjacent to the rear edge of a rectangular ground glass arranged in this top wall; this arrangement enables positioning of this exposure meter either superposed upon this ground glass with the photoelectric cell facing this glass, or normal to this position with the photoelectric cell facing the object to be photographed and the top wall of the exposure meter with the pointer facing the operator of the camera. It is evident that this arrangement further enables handy and convenient tilting of the exposure meter from one measuring position to the other, and simultaneously easy reading of the pointer indications.

In accordance with my invention, 1 further combine with the exposure meter, shortly described above, an exposure meter scale being arranged on the top wall of the exposure meter and extending substantially to the front edge of this wall and cooperating with the pointer of the meter; this scale cooperates with the arrangements for adjusting the factors aifecting the exposure being arranged on the front wall of said camera casing and extending substantially to said exposure meter edge, thus enabling easy and simple adjusting of these factors in accordance with the indications of the exposure meter pointer.

The novel features which I consider as characteristic for my invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional. objects and advantages thereof will be best understood from the following description of specifiic embodiments, when read in connection with the accompanying drawing, in which:

Fig. 1 shows a cross-section of a reflex camera equipped with my new exposure meter arrange ment, in one position;

Fig. 2 the camera shown in Fig. l, in another position;

Fig. 3 a top view of the camera shown in Fig. 1;

Fig. 4 a top view of another embodiment of my the diaphragm opening of the camera, means camera; for setting the speed of the camera shutter and Fig, a front view of the camera shown in means for sliding the camera. lens in axial direc- Figs. 1 and 3; and tion.

Fig. 6 a front view of another embodiment of 5 These means for adjusting the diaphragm my new camera. opening consist in a rotating ring-shaped mem- As shown in Figs. 1 and 2, the camera comber 24 arranged on the front wall l3 coaxially prises a camera casing I I, a camera lens I 2 in with the lens mount 28. This ring-shaped memthe front wall l3 of this casing II, a viewing ber may be provided with a pointer, lever, promember including a ground glass l4 in the top jecting member, or the like, extending near or wall l5 of this casing, and a reflecting mirror [6 to the edge 23 of the exposure meter. By means arranged within this casing and adapted to re of this projecting member it is possible to set in flect the light rays entering casing l I through an easy and simple way the diaphragm opening lens l2 onto ground glass [4, forming thereby an in accordance with the indications of the expoimage of the object to be photographed on this sure meter pointer.

ground glass. In order to facilitate this operation I may pro- The above enumerated elements are usually vide an additional scale system 29 on the outer used, well-known elements of many types of resurface of the camera casing, e. g., on its front flex cameras, their constructive details and their wall l3 connecting the scale of the exposure mode of operation are well-known to everbody meter with the rotating diaphragm adjusting skilled in this art and will, therefore, not be dering 24. (Fig. 5).

scribed in detail. I may provide, as furthermore shown, on the In accordance with my present invention, I adjusting ring 24 a mark 25 cooperating with the pr vi n the p w l I f the c ing a ph t scale system 29, further facilitating thereby the electric exposure meter l6, secured by hinges I! 25 setting of the diaphragm,

the eto- This exposure meter comprises an In another embodiment of my invention I may,

some m er body l8 p vided o its bott m face as shown in Fig. 4, omit the separate exposure with a light-sensitive cell l9 and on its top face meter scale on the top of the exposure meter with a pointer 20 cooperating Wi h e light" body and shape the pointer 26 in such a manner sensitive ce l 9 and indicating the te y 0f that it reaches to edge 23 of the casing, cooperatth light p ng on th ut surface of this in directly with scale 29 or the projecting memcell. I want to note that the light-sensitive cell h of th adjusting ring 24. 8 is preferably composed of a series of small I t to not that the diaphragm scale 21, independent, pelallelly Connected cellsshown in Fig. 3, needs not to be arranged on the As shown in Fig, 1, this exposure meter can be ring 24; I may also provide the diaphragm scale tilted into a position in which it is substantially 30 on t top 9f th cam a casing a h w in perp e p ground glass M with t photo- Fig. 4, or on the top part of the front wall as electric cell is f i i r nd l ss; in this shown in Fig. 6, in such a position that it is adjaposition each of the small cells is oppositea small t t edge 23 of th exposure t if th Dori/10h 0f the image P j d o the glfollnd exposure meter is in the position shown in Fig. 1. glass a us measures the light intensity of In this case I have, however, also to provide the respective image portion only. As these cells means, g gear train, levers, or t k t are connected p y, they all influence the transmit the regulating impulses from the adjustmeasurement indicated by pointer they give, ing member 3i sliding along this scale.

however, a more correct indication of the av- I may also t this Scale 39 and use this sliderage light intenslty of the image than could be m adjusting member 3 1 this case I have achieved by a single cell with a great light-Sen to watch that the point of member 3| be in corresitive surface. By tilting the exposure meter spondence with the point of pointer 26,

around hinges H in the direction indicated by Instead of using a square-shaped phofigmeter arrow 2i, it reaches the position shown in Fig. 2, body I may use one with a cynndrical m i. 6-, it is positioned normal to ground g1a5s |4 tion and provide a photometer pointer bent over and top wall l5 facing with the light-sensitive this edge and Sliding with its point along this Photo-electric Ce 11 the Object to f cylindrical front face of the photometer body. graphed, and with its top Wa l O which the In this case it is especially easy to bring the pointer 20 is arranged facing the operator of the point of th photometer pointer in correspond- 00 Camera- I ence with the diaphragm scale on the camera The Optimum of my new exposure meter 15 front wall or with a diaphragm regulating memthe fo ow ber sliding along the upper edge of this wall.

If I Want to measure the light mten1tY of the It will be understood that each of the elements image f01med On ground gl M I f (m described above, or two or more together, may also Dosure meter Into theposltlon Shown m 1; find a useful application in other types of reflex when the F meter 15 F be used meas' cameras differing from the types described above. uring the intensity of the light rays emitted or While I have illustrated and described the reflected by the be photogtaphed invention as embodied in reflex cameras, I do not if t exposure meter 15 to be used 1n the usual intend to be limited to the details shown, since Way, it is tilted into the Position shown in various modifications and structural changes As shown in the top Wall of the may be made without departing in any way from posure meter body l8 may be provided with a th i it of my i v tion, scale 22 cooper t g With pointer It is Without further analysis, the foregoing will so importance a as shown in s fi this 7 fully reveal the gist of my invention that others scale extends substantially to the front edge 23 can by applying current knowledge readily adapt of the exposure meter body l6. As shown in Fi it for various applications without omitting fea- 5, on the front wall l3 of camera casing H are tures that, from the standpoint of prior art, fairly arranged all means for adjusting the factors constitute essential characteristics of the generic affecting the exposure, i. e., means for adjusting or specific aspects of this invention, and therefore such adaptations should and are intended to camera casing in such a manner as to enable be comprehended within the meaning and range positioning of said exposuremeter either superof equivalence of the following claims. p sed up n sa d v ewing mem er w t t p What I claim as new and desire to secure by electric cell facing this member, or normal to this Letters Patent is: 6 position with the top wall of the exposure meter 1. In a reflex camera a camera casing, a frontal with the pointer facing the operator of the camlens in the front wall of said casing, a viewing era and with the photo-electric cell facing the member in the top wall of said casing, a reflecting object to be photographed, said securing means mirror within said casing adapted to reflect the and that p r o the camera asi g wh ch is light rays entering the casing through said lens 10 located between said securing means and the onto said viewing member and thus to project an upper front edge of said camera casing being image of the object to be photographed on this arranged and shaped in such a manner that lightmember, a photo-electric exposuremeter comrays emitted or reflected by the object to be prising a photo-electric cell and a pointer, and photographed in direction of said camera casing means securing at least said photo-electric cell are unobstructedly impinging upon said phototo the top wall of said camera casing movably electric cell when said exposure meter is in a between a position in which the light-sensitive po i ion normal to said viewing member with the surface of said photo-electric cell faces said viewp t -e ectric cell facing the object to be D ing member and the image projected on it, and a tc p position in which this surface is facing the object In a r flex camera a camera casing, a camto be photographed, said securing means and t t era lens in the front wall of said casing, a viewing part of said camera casing which is located member p ng a rectangular gro glass between said securing means and the front edge arranged n t e op of said casing with its edge of said camera casing being arranged and shaped pa a l t the edges t a fl t g mirr r in such a manner that li ht rays tt or within said casing adapted to reflect the light reflected by the bj ct t b photographed in rays entering the casing through the camera lens direction of said camera casing are unobstructedonto said gro d ass a d to o m thus on the ly impinging upon the light-sensitiv urfac of ground glass an image of the object to be photosaid photo-electric cell when the same is in a graphed, a substantially flat photo-electric position in which this surface is facing the object P te comprising an exposuremeter body, to be photographed a photo-electric cell arranged on its bottom wall,

2. In a reflex camera a camera casing, a camand a cooperating o r a d n its t p era lens in the front wall of said casing, a Viewing wall, and hinge-like means securing said expomembcr comprising a rectangular ground glass sul'emeter along one of its edges to the top wallof arranged on the top of said casing with its edges 5 the Camera Casing adjacent to he rear edge of parallel to the edges thereof, a reflecting mirror Said rectangular ground a enabling thereby it n'Said casing adapted to reflect the light positioning of said exposuremeter either superrays entering the casing through the camera lens posed 1113011 Said ground glass With the P onto said ground glass and to fo thus on the electric cell facing this ground glass or normal ro nd glass an image of t object to be photo 40 to this position with the top wall of the exposure graphed, photo-electric exposuremeter meter equipped with the pointer facing the operprising a photo-electri 11 and a pointer, and ator of the camera and with the photo-electric hinge-like means securing at least said photo cell facing the object to be photographed, said electric cell along one of its edges to the top Wall Securing means and that part Of the 17011) O a of the camera casing adjacent to the rear edge of camera casing which 'is located between Said said rectangular ground glass turnably between a hingemke means and the upper front edge C position in which the light-sensitive surface of said camera casing being arranged and Shaped said photoelectric cell faces said ground glass in Such a manner that light-rays emitted 0 and the image projected on it and a position in r reflected by the Object to b photographed in which t surfa is fa in the object to be do direction of said camera are unobstructedly imphotographed, said hinge-like mean a t t pinging upon said photo-electric cell when said part of t t of Said camera casing which is exposure meter is in a position normal to said located between said hinge-like means and the Viewing member with said Photo-electric C811 upper front edge of said camera casing being facing the Object to be photographedarranged and shaped in such a manner that lighta reflex Camera a camera casing, a camera rays omitted or reflected by the object to be lens m the from Wall of Sam casing, Viewing photographed in direction f Said camera casing member in the top wall of said casing, a reflecting are unobstructedly impinging upon the gm-F mirror arranged within said casing and adapted sensitive surface of said photo-electric cell when to reflect the light rays entering the Casing the same is in a position in which this surface is through Said Camera lens Onto Said Viewing facing the object to be photographe her, and to project thus an image of the object to 3. In a reflex camera a camera casing, a camera be photographed on this member, a Substantially lens jn the front wall f said casing, a viewing flat photo-electric exposure meter comprising an member in the top wall of said casing, a reflecting exposure meter body a photo'electric c911 mirror arranged within said casing and adapted ranged on its bottom wall, and a cooperating to reflect the light rays entering the casing P01111581 arranged on its top wall, means s curing through said camera lens onto said viewing memsaid exposure meter movably to said camera bar, and to project thus an image f the Object ing in such a manner as to enable positioning of to be photographed on t member a Substam said exposure meter either superposed upon said tially flat photo-electric exposuremeter comprisviewin m r th t e photo-e ectric cell facing an exposuremeter body, a photo-electric cell lng this member, normal to s p on W arranged on its bottom wall, and a cooperating the photo-electric cell facin the object to be pointer arranged on its top wall, and means photographed and the top wall of the exposure securing said exposuremeter movably to said meter with the pointer facing the operator of the camera, an exposure meter scale being arranged lectric cell facing this member, or normal to this on the top wall of said exposure meter and exposition with the photo-electric cell facing the tending substantially to the front edge of said object to be photographed and the top wall of wall and cooperating with the exposure meter the exposure meter with the pointer facing the pointer, and a diaphragm adjusting arrangement operator of the camera, an exposure meter scale bein arranged on the front wall of said camera being arranged on the top Wall of said exposure casing and extending substantially to said expometer and extending substantially to the front sure meter edge, thus enabling easy and simple edge of said wall and cooperating with the exsetting of the diaphragm Opening in accordance posure meter pointer, a movable member for adwith the indications of the exposure meter lusting the diaphragm of the camera, said mempointer. her being arranged on the front wall of said cam- 6. In a reflex camera a camera casing, a camera Casing, a d a Sc e System on the outer surera lens in the front wall of said casing, a viewf e Of Sa d Ca e a Casi g connecting the scale ing member in the top wall of said casing, a reof s p sure meter with said movable diafleeting mirror arranged within said casing and phragm adjusting member, thus enabling easy adapted to reflect the light ray entering the oasand S pl djusting f t ese factors in according through said camera lens onto said viewing -f e with the indication of the exposure meter member, and to project thus an image of the obp ject to be photographed on this member, a sub- In a reflex camera a ca e a casing, a camstantially flat photo-electric exposure meter come lens in the from} W Of Said Casing, a viewprising an exposure meter body, a photo-electric member comprlslhg a rectangular g o d cell arranegd on its bottom wall, and a cooperatglass arranged on the p f S d C s ng with its ing pointer arranged on its to w ll, means edges parallel to the edges thereof, a reflecting curing said exposure meter movably to said cammlrror Within Said Casing adapted to reflect the era casing in such a manner as to enable posilight rays entering he sing through the camtioning of said exposure meter either superposed era lens Onto Saidgrolmd ass and to form thus upon said viewin member with the photo-elecon the ground glass n age of the object to be tric cell facing this member, or normal to this photographed, a subs antially flat photo-electric position with the photo-electric cell facing the eXDOSUrB meter Comprising n exposure meter object to be photographed and the top wall of body, a photo-electric e l composed of a pluthe exposure meter with the pointer facing the faulty of elements of Cells Parallelly Co n c ed operator of the camera, an exposure meter scale and ed on the bottom wall of said exposure being arranged on the top wall of said exposure meter y, and a cooperati po nter arranged meter and extending substantially to the front on Its top Well, and ke means securing edge of said all and cooperating with th EX- Said exposure meter along one (If edges to the posule meter pointer, and a movable member for tOP Well of the eamem Casing a ent to the rear adjusting the diaphragm of the camera, said edge of Said rectangular ground s enabling member being arranged on the front wall of said thereby Positioning f S d exposure meter either camera casing and extending substantially to superposed upon Said u d glass with the said exposure meter edge, thus enabling easy and Photo-electric Cell facing s ground ss or simple adjusting of these factor in accordance al to this position with the top wall of the with the indication of the exposure meter pointer. D 'e te qu pped With the pointer fac- 7. In a reflex camera a camera casing, a caming the Operator of the camera and with the era lens in the front wall of said casing, a viewphoto-electric cell facing the Object t0 be P ing member in the top wall of said casing a re phed, saidsecuring mea s and that part of fleeting mirror arranged within said casing and the D Of Bald C a casing which i located adapted to reflect the light rays entering the casbetween Said hinge-like means and the pp ing through said camera lens onto said viewing f t edge t i Camera casing e n r nged member, and to project thus an image of the oband shaped in Such a manner that ays ject'to be photographed on this member, a subemitted reflected by e 18 at to be photostantially fiat photo-electric exposure meter graphed 1h dlleetlcn of said ca mera ar unobco p ising an posure meter body, a photostructedly impinging upon said photo-electric electric cell arranged on its bottom wall, and a Cell n d exposure meter is in a p s t o ooperating pointer arranged on it tOp n normal to said viewing member with said photomeam securing said exposure meter movably to electric 11 facing e bje t t be photosaid camera casing in such a manner as to enable grephedpositioning of said exposure meter either super- JACQUES SE posed upon said viewing member with the photo- 

